Method and apparatus for selective axial ejection
AssigneeSciex Division of MDS Inc.
InventorsAlexander Loboda, Frank Londry
Life of this patent
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Abstract
A mass spectrometer system and a method of operating a mass spectrometer having an elongated rod set, the rod set having an entrance end, an exit end, a plurality of rods and a longitudinal axis, involving (a) admitting ions into the entrance end of the rod set; (b) producing an RF field between the plurality of rods to radially confine the ions in the rod set; (c) providing a static axial electric field within the rod set; and (d) separating the ions into a first group of ions and a second group of ions by providing an oscillating axial electric field within the rod set to counteract the static axial electric field, wherein the oscillating axial electric field varies along the longitudinal axis of the rod se.
Claims28
A method of operating a mass spectrometer having an elongated rod set, the rod set having an entrance end, an exit end, a plurality of rods and a longitudinal axis, the method comprising:
- (a) admitting ions into the entrance end of the rod set;
- (b) producing an RF field between the plurality of rods to radially confine the ions in the rod set;
- (c) providing a static axial electric field within the rod set;
- and
- (d) separating the ions into a first group of ions and a second group of ions by providing an oscillating axial electric field within the rod set to counteract the static axial electric field, wherein the oscillating axial electric field varies along the longitudinal axis of the rod set.
A mass spectrometer system comprising:
- (a) an ion source;
- (b) a rod set, the rod set having a plurality of rods extending along a longitudinal axis, an entrance end for admitting ions from the ion source, and an exit end for ejecting ions traversing the longitudinal axis of the rod set;
- and,
- (c) a power supply module for producing an RF field between the plurality of rods of the rod set, wherein the power supply module is coupled to the rod set to provide a selected static axial electric field and a selected oscillating electric field such that (i) the selected oscillating axial electric field varies along the longitudinal axis of the rod set, and (ii) the selected static axial electric field and the selected oscillating axial electric field counteract each other to separate the ions into a first group of ions and a second group of ions based on a selected mass-to-charge ratio.
Dependencies are inferred from the claim text.